An apparatus and method for providing a ringing voltage to a communication device such as a telephone or a modem. Typically, communication devices are coupled to a ringing voltage providing telephone network, such as a Plain Old Telephone Service (POTS) network. The POTS network generally provides the necessary ringing voltages to the communication device. However, in other telephone networks, such as a PBX system, ringing voltages are not provided by the telephone network. The apparatus provides ringing voltages to the communication devices coupled to the non-ringing voltage providing telephone networks. The apparatus includes a switching regulator that provides the necessary ringing voltages to an indicator such as a bell or other output indicator.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A modem adapted for use with a non-ringing voltage producing (n-RVP) telephone network, comprising: an analog front end (AFE) circuitry adapted to perform communication functions; a RING conductor coupled to the AFE circuitry; a TIP conductor coupled to the AFE circuitry; and a feedback-controlled ringing voltage source, coupled to the RING conductor and the TIP conductor, the ringing voltage source adapted to generate a ringing voltage on the RING conductor and the TIP conductor responsive to a ring control signal from the n-RVP telephone network.
2. The modem of claim 1 , the ringing voltage source comprising: a ring control signal line, couplable to the n-RVP telephone network and adapted to receive the ring control signal; a switching regulator adapted to generate an output signal on an output signal line coupled to the RING conductor and the TIP conductor; and a feedback circuit, coupled to the switching regulator and the ring control signal line, wherein the switching regulator is adapted to place a ringing voltage on the output signal line responsive to feedback from the ring control signal and the output signal.
3. The modem of claim 2 , wherein the feedback circuit is adapted to modulate the output signal on the output signal line responsive to the ring control signal.
4. The modem of claim 1 , wherein the ring control signal is an AC signal.
5. The modem of claim 1 , further comprising: a DC input voltage, coupled to an input of the switching regulator and coupled to the RING conductor and the TIP conductor.
6. The modem of claim 1 , the feedback circuit comprising: an operational amplifier, an output of the operational amplifier coupled to a feedback input of the switching regulator, a first input of the operational amplifier coupled to the ring control signal line, and a second input of the operational amplifier coupled to the RING conductor and the TIP conductor.
7. The modem of claim 1 , wherein the n-RVP telephone network is a private branch exchange.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
September 16, 1999
March 2, 2004
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